TM 55-1520-240-23-4
5-6
INSPECT ROTARY-WING HEADS
(Continued)
5-6
Horizontal hinge pins with serial
numbers of UW2407 and prior that do
not have a suffix "A" vibro engraved
after the serial number and with total
time since new of 4800 flight hours
or more must be replaced.
NOTE
Paint removal is not required for
rotary-wing head inspection. Use
flashlight and mirror for hidden areas.
Procedures can be used to inspect
forward and aft rotary-wing heads.
1.
Check all surfaces of rotary-wing head (1),
including webs (2), lugs (3), and holes (4). There
shall be no cracks, burns, or pits. If a crack is
suspected, refer to TM 1-1520-253-23.
NOTE
Burns and pits indicate lightning
strikes.
2.
Check rotary-wing head (1) for scores, nicks, or
gouges that have gone through paint. Check that
damage is within rework limits as follows:
a.
Damage to top hub face (5) and bottom hub
face (6) shall not exceed 0.005 inch in depth
by 2.5 inches in length or 0.010 inch in
depth by 1.0 inch in length.
b.
Damage to six lugs (7), webs (8), and side
surfaces (9) shall not exceed 0.005 inch in
depth by 0.625 inch in length.
5-32
